Rangkaian Skema Elektronika

artikel penjelasan komponen belajar skema rangkaian elektronika

Rangkaian Lampu LED Sepeda Motor ini sangat sederhana yang hanya menggunakan beberapa komponen saja tapi hasilnya sangat memuaskan. Konsumsi dayanya sangat kecil cukup 6 Volt saja sangat cocok untuk sepeda motor anda.The 555 circuit below is a flashing bicycle light powered with four C,D or AA cells (6 volts). Two sets of 20 LEDs will alternately flash at approximately 4.7 cycles per second using RC values shown (4.7K for R1, 150K for R2 and a 1uF capacitor). Time intervals for the two lamps are about 107 milliseconds (T1, upper LEDs) and 104 milliseconds (T2 lower LEDs). Two transistors are used to provide additional current beyond the 200 mA limit of the 555 timer. A single LED is placed in series with the base of the PNP transistor so that the lower 20 LEDs turn off when the 555 output goes high during the T1 time interval. The high output level of the 555 timer is 1.7 volts less than the supply voltage.

Adding the LED increases the forward voltage required for the PNP transistor to about 2.7 volts so that the 1.7 volt difference from supply to the output is insufficient to turn on the transistor. Each LED is supplied with about 20mA of current for a total of 220mA. The circuit should work with additional LEDs up to about 40 for each group, or 81 total. The circuit will also work with fewer LEDs so it could be assembled and tested with just 5 LEDs (two groups of two plus one) before adding the others.

Rangkaian LED Berjalan 24 kanal. It is 24 channel light illumination. The schematic is very simple – 24 LED’s, 1 MCU and some additional components. The main principle is dynamic indication, which is usually implemented for control of 7-segment digital indicators. Here is the same, as for indicators are used traditional 5-mm LED’s.

For control unit is implemented not expensive MCU ATTYNI2313 (Atmel), which can drive direct LED (up to 20 mA on each pin). As you can see on the schematic, 24 LED’s are grouped in 4 groups, each one consist 6 LED’s. LED’s in group 1 indicate the content of register r0 of MCU, LED’s in group 2 – r1, LED’s in group 3 – r3 and LED’s in group 4 indicate the content of register r3. Dynamic indication do this, as in each moment of time indicates content of one register and scans them consecutive. For instance, when the content of r1 is loaded in output port (PORTB), the transistor Q2 is switched "ON", and the LED of group 2 indicate the bits in r1.

There are 3 buttons – "F", "+" and "-". The button F is for change of effect, and buttons "+" and "–" are for increasing or decreasing the speed of effect. For example, each time when you press button "-" changing of lights go more slowly. For fast changing of speed you can press and hold the appropriate button.

The speed of effects is independent of speed of dynamic indication, which is constant.

The schematic can be powered by any DC adapter for 8 to 15 V / 100mA. I use 12V adapter and for the stabilizer 7805 there is no need of heat sink for them – this is one of advantages of implementation of dynamic indication. Others advantages are simple schematic and PCB, lower pin count of MCU etc.

Software is written in assembler of IDE AVRStudio 4. The program code is below. There are a lot of comments for explanation how the program works. With simple changes in code everyone can make different effects and/or add them. Each effect can be up to 24 stages.

If the LED pins are made longer with additional wires, LED effects can be used for Christmas tree or for advertising text on shop window (for instance). If there is need, LED number can be easy increased up to 32 LED’s and stages. Enjoy!